Hawaiian Sen. Daniel Inouye, a Democrat, has died of respiratory complications, according to his office. Sen. Inouye was 88 years old and a veteran of World War II. He had held his Senate seat since 1963; before that, he served in the House of Representatives, meaning he had represented Hawaii in Congress since it became a state in 1959.

Sen. Inouye was hospitalized last week, after complications from a lung surgery in the 1960s flared up. According to his staff, his final word was "Aloha."

Inouye was the chairman of the Committee on Appropriations, and was also the President pro tempore, making him third in line for succession of the presidency, after Vice President Joe Biden and Speaker of the House John Boehner. Inouye's pro tempore title will now likely fall to Sen. Patrick Leahy of Vermont.

Inouye was also awarded the Medal of Honor by President Bill Clinton for heroism for his service in the Second World War. During a raid in Italy, Inouye single-handedly protected his platoon from German forces, losing his right arm in the process. Inouye tells the remarkable story in Ken Burns' much-lauded documentary The War.

Inouye's seat will be filled by an appointment by Gov. Neil Abercrombie (D). He will pick from three finalists provided by the state Democratic Party. State law requires that Inouye must be replaced by a senator from the same political party. Inouye's seat is up for a full term in 2016.